Utility AI Plugin - Curve Functions

SUtilityResponseCurveWidget.cpp

for (int32 PointIndex = 0; PointIndex < NumPoints; ++PointIndex)
{
    const float X = PointIndex / (NumPoints - 1.0);
    
    // Process value with the set curve function
    float Y = (*CurveFunction.Get())(X, Slope.Get(), Exponent.Get(), HShift.Get(), VShift.Get());

    if (bInvert.Get()) Y = 1 - Y;

    // Handle Y values outside of normalized graph
    if (Y < 0 || Y > 1) continue;

    // Handle undefined points
    if (FMath::IsNaN(Y)) continue;

    Points.Add(PointsTransform.TransformPoint(FVector2D(X, Y)));
}

UtilityAITypes.cpp

namespace FUtilityResponseCurveFunctions
{
	const FUtilityResponseCurveFunction Default 	= [](const float X, const float M, const float K, const float B, const float C){ return 0.f; };
	const FUtilityResponseCurveFunction Binary		= [](const float X, const float M, const float K, const float B, const float C){ return X > 0.5f ? 1.f : 0.f; };
	const FUtilityResponseCurveFunction Linear 		= [](const float X, const float M, const float K, const float B, const float C){ return M * (X - B) + C; };
	const FUtilityResponseCurveFunction Polynomial 	= [](const float X, const float M, const float K, const float B, const float C){ return M * pow(X - B, K) + C; };
	const FUtilityResponseCurveFunction Sine 		= [](const float X, const float M, const float K, const float B, const float C){ return M * sin(UE_HALF_PI * (X - B)) + C; };
	const FUtilityResponseCurveFunction Cosine 		= [](const float X, const float M, const float K, const float B, const float C){ return M * cos(UE_HALF_PI * (X - B)) + C; };
	const FUtilityResponseCurveFunction Logistic 	= [](const float X, const float M, const float K, const float B, const float C){ return C / (1 + pow(UE_EULERS_NUMBER, -K * (X - B))); };
	const FUtilityResponseCurveFunction Logit 		= [](const float X, const float M, const float K, const float B, const float C){ return M * log(X / (1 - X)) + C; };
}

UtilityAITypes.h

/* 
 * Declares a type alias for response curve functions.
 * Parameters that get passed in:
 * X = input value
 * M = slope
 * K = exponent
 * B = horizontal shift
 * C = vertical shift
 */
using FUtilityResponseCurveFunction = TFunction<float(float /* X */, float /* M */, float /* K */, float /* B */, float /* C */)>;

namespace FUtilityResponseCurveFunctions
{
	extern const FUtilityResponseCurveFunction Default;
	extern const FUtilityResponseCurveFunction Binary;
	extern const FUtilityResponseCurveFunction Linear;
	extern const FUtilityResponseCurveFunction Polynomial;
	extern const FUtilityResponseCurveFunction Sine;
	extern const FUtilityResponseCurveFunction Cosine;
	extern const FUtilityResponseCurveFunction Logistic;
	extern const FUtilityResponseCurveFunction Logit;
}

UtilityConsideration.cpp

void UUtilityConsideration::SetCurveFunction()
{
	if (!CurveFunction) return;

	switch (CurvePreset)
	{
		case EResponseCurvePreset::Binary:		CurveFunction = FUtilityResponseCurveFunctions::Binary; break;
		case EResponseCurvePreset::Linear:		CurveFunction = FUtilityResponseCurveFunctions::Linear; break;
		case EResponseCurvePreset::Polynomial:	CurveFunction = FUtilityResponseCurveFunctions::Polynomial; break;
		case EResponseCurvePreset::Sine:		CurveFunction = FUtilityResponseCurveFunctions::Sine; break;
		case EResponseCurvePreset::Cosine:		CurveFunction = FUtilityResponseCurveFunctions::Cosine; break;
		case EResponseCurvePreset::Logistic:	CurveFunction = FUtilityResponseCurveFunctions::Logistic; break;
		case EResponseCurvePreset::Logit:		CurveFunction = FUtilityResponseCurveFunctions::Logit; break;
		default:								CurveFunction = FUtilityResponseCurveFunctions::Default; break;
	}
}